I don't think it matters.
Like it or not we are going to learn to run our bikes on ethernol - or something other than straight petrol.
In 10 years time, if you can buy it, straight petrol will be 20 bucks a litre.
Modern oils apparently aren't suitable for our engines. We fit filters.
Unleaded petrol isn't suitable for our engines. We fit valve inserts and alter the jetting.
We adapt.
Given time, advice from experienced people and a bit of trial and error we'll be running our beesa's on 100% ethernol and loving it.
We may have to stick our plastic tanks on the shelf and use tins.
We may have to learn what bits get eaten by the green juice and replace them with bits that are vaccinated against it.
So, we have to modify our bikes again. So what. The only factory original bikes you see these days arrive and leave on a trailer anyhow.
This does not just affect BSAs. There are some very clever people out there who will come up with solution(s)
With petrol rationing during the second world war they ran engines on all sorts of stuff.
cheers